This invention relates to an automatic drip coffee maker having a new flow-through heater/warmer plate assembly. Specifically, a spring wire clamp holds the heater centered against the bottom of the warmer plate.
Typical automatic drip coffee makers (ADC""s) have a pedestal with a cold water reservoir, a head projecting forwardly from the upper end of the pedestal which houses a brew basket, and a base projecting from the lower end of the pedestal which houses a flow-through heater. The base usually has an upper wall having an opening for a warmer plate that is aligned with the brew basket upon which a carafe can be positioned for receiving brewed coffee from the brew basket. In many cases, the upper wall is molded integrally with the lower part of the pedestal and has depending front and side wall members to form the cavity for the flow-through heater. A separate bottom cover connected to the upper wall closes the bottom of the housing base.
One conventional flow-through heater includes an elongate, rope-like heating element bent to a U-shape and a water pipe beneath and substantially coextensive with the heating element. The water pipe and the heating element have a common rigid housing and are in good thermal contact with one another. The warmer plate, which is located above the opening in the upper wall of the housing base is drawn downwardly into engagement with the upper wall of the base by means of a threaded post welded to the bottom center of the warmer plate and a nut engaged with the post which is tightened against the outside bottom surface of the bottom cover. A clamp bar held by another nut threaded on the post holds the heater against the bottom surface of the warmer plate. This style of construction may cause a warmer plate to warp, so it is necessary to apply a thermal conducting compound between the heating element and warmer plate to achieve a reliable thermal contact between them.
In a further embodiment, a single, metal spring clip may be attached to a support ring. The clip is positioned so that it extends in one, straight line across the U-shaped heating element and urges it upwardly against the bottom of the warmer plate. This straight clamp is intended to center and hold the heating element tight onto the warmer plate. However, the contact of the spring along a single axis allows the heating element to have some rotational movement. Further, in the event of any warping of the warming plate or the support ring, the securement against the bottom of the warmer plate is not necessarily reliable.
Accordingly, it is an object of the present invention to overcome the foregoing drawbacks and provide a reliable assembly for centering a heater against of the warmer plate in an ADC.
In one embodiment, a coffee maker heater/warmer plate assembly comprises a support ring, a warmer plate, a flow-through heater and a spring clamp. The support ring is adapted to engage the outside edge of the top of the warmer plate. The spring clamp has ends that are adapted to be engaged with the support ring wherein the spring clamp further engages the flow-through heater and biases the flow-through heater against the bottom of the warmer plate. The spring clamp further comprises two legs, each having opposite ends engaging mutually spaced apart shoulders on the supporting ring. Intermediate portions of the legs of the spring clamp engage both the bottom and side surfaces of the flow-through heater. Alternatively, the spring clamp may comprise a single, V-shaped wire. The spring clamp may be comprised of steel wire. Additionally, the support ring may comprise three shoulders that are spaced approximately 120 degrees from each other, and the ends of the spring clamp engage the shoulders. Still further, the flow-through heater may be substantially U-shaped.
In a further embodiment, a coffee maker heater/warmer plate assembly comprises a warmer plate, a flow-through heater, spring clamp means, and a support ring. The spring clamp means retain the heater and bias it against the bottom of the warmer plate. The support ring further comprises means for securing the spring clamp means. The spring clamp means comprises two legs and is adapted to engage both the bottom and side surfaces of the heater, thereby confining the heater both horizontally and vertically on the bottom of the warmer plate. The spring clamp means may comprise a single, V-shaped wire. That wire may be comprised of steel. Still further, the securing means may be spaced approximately 120 degrees from each other. The flow-through heater may be substantially U-shaped.